Method for forming metallization structure

ABSTRACT

Graphene oxide is used as an insulation barrier layer for metal deposition. After patterning and modification, the chemical characteristics of graphene oxide are induced. It can be used as the catalyst for electroless plating in the metallization process, so that the metal is only deposited on the patterned area. It provides the advantages of improving reliability and yield. The metallization structure includes a substrate, a graphene oxide catalytic layer, and a metal layer. It may be widely applied to the metallization of the fine pitch metal of a semiconductor package as well as the fine pitch wires of a printed circuit board (PCB), touch panels, displays, fine electrodes of solar cells, and so on.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of pending U.S. patent application Ser.No. 15/851,054, filed on Dec. 21, 2017 and entitled “Metallizationstructure AND MANUFACTURING METHOD THEREOF”, the entirety of which isincorporated by reference herein.

TECHNICAL FIELD

The disclosure relates to a metallization structure and manufacturingmethod thereof.

BACKGROUND

As electronic products are being developed in ways that make themlighter, thinner, smaller and more multi-functional, the functions ofchips and packages are increasing. The demand for high-density circuitwill be unavoidable. The shrinkage of line pitch has become a majorchallenge. Traditional metallization processes for fine pitch metalinclude conducting-layer deposition, lithography, electroplating, andetching. The whole process uses up a lot of materials, chemical solventsand water resources. Therefore, the harm being done to the environmentis a worry for the future development of the electronics industry.

A semi-additive method is currently used in the metallization process.The barrier/seed layer is deposited by a physical vapor deposition (PVD)method. After formation of the circuit, a wet etching process is used toremove the unwanted barrier and/or seed layer.

As the pitch of the circuit shrinks, incomplete etching or over-etchingmay be cause issues with reliability and yield.

Accordingly, a novel metallization structure for the current field ofpatterned metallization of fine pitch circuit is called for.

SUMMARY

An embodiment of the disclosure provides a metallization structure,including a substrate; a graphene oxide catalytic layer; and a metallayer, wherein the graphene oxide catalytic layer is disposed betweenthe substrate and the metal layer.

Another embodiment of the disclosure provides a metallization structure,including a substrate; a graphene oxide layer, disposed on thesubstrate; a graphene oxide catalytic layer; and a metal layer, whereinthe graphene oxide catalytic layer is disposed between the grapheneoxide layer and the metal layer.

Still another embodiment of the disclosure provides a method for formingthe metallization structure, comprising: providing a substrate; forminga graphene oxide layer on the substrate; modifying the graphene oxidelayer to form a graphene oxide catalytic layer; and performing ametallization process on the graphene oxide catalytic layer.

A detailed description is given in the following embodiments withreference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The present disclosure can be more fully understood by reading thesubsequent detailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 illustrates a schematic view of a metallization structure inaccordance with an embodiment of the present disclosure;

FIG. 2 illustrates a schematic view of a patterned metallizationstructure in accordance with another embodiment of the presentdisclosure;

FIG. 3A illustrates a cross section of a metallization structure duringthe manufacturing method for forming the metallization structure inaccordance with an embodiment of the present disclosure;

FIG. 3B illustrates a cross section of a metallization structure duringthe manufacturing method for forming the metallization structure inaccordance with an embodiment of the present disclosure;

FIG. 3C illustrates a cross section of a metallization structure duringthe manufacturing method for forming the metallization structure inaccordance with an embodiment of the present disclosure;

FIG. 3D illustrates a cross section of a metallization structure duringthe manufacturing method for forming the metallization structure inaccordance with an embodiment of the present disclosure;

FIG. 3E illustrates a cross section of a metallization structure duringthe manufacturing method for forming the metallization structure inaccordance with an embodiment of the present disclosure;

FIG. 4A illustrates a cross-sectional view of intermediate stages of amethod for fabricating the metallization structure in accordance withanother embodiment of the present disclosure;

FIG. 4B illustrates a cross-sectional view of intermediate stages of amethod for fabricating the metallization structure in accordance withanother embodiment of the present disclosure;

FIG. 4C illustrates a cross-sectional view of intermediate stages of amethod for fabricating the metallization structure in accordance withanother embodiment of the present disclosure;

FIG. 4D illustrates a cross-sectional view of intermediate stages of amethod for fabricating the metallization structure in accordance withanother embodiment of the present disclosure;

FIG. 4E illustrates a cross-sectional view of intermediate stages of amethod for fabricating the metallization structure in accordance withanother embodiment of the present disclosure; and

FIG. 4F illustrates a cross-sectional view of intermediate stages of amethod for fabricating the metallization structure in accordance withanother embodiment of the present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

The term “an embodiment” in the following context means a particularpattern, structure, or feature described in connection with at least oneembodiment of the present disclosure. Therefore, the followingdescription of “in an embodiment” does not refer to the same embodiment.In addition, the particular patterns, structures, or features in one ormore embodiments may be combined in any suitable manner. It should benoted that, in the drawings, the size of some of the elements may beexaggerated for illustrative purposes and are not drawn to scale. Thedimensions and the relative dimensions do not correspond to actualdimensions in the practice of the disclosure.

The present disclosure uses graphene oxide as an insulation barrierlayer for metal deposition. After patterning and modification, thechemical characteristics of a patterned area of the graphene oxide areinduced and can be used as the catalyst for electroless plating.Therefore, the metal is only deposited on the patterned area andcompletes the metallization process.

In some embodiments of the present disclosure, the graphene oxide isused as an insulation barrier layer and a seed layer. Referring to FIG.1, a metallization structure 10 is provided. The metallization structure10 includes a substrate 11, a graphene oxide layer 12, a graphene oxidecatalytic layer 13, and a metal layer 14. The graphene oxide catalyticlayer 13 is disposed between the substrate 11 and the metal layer 14. Inthis embodiment, a patterned structure is disposed above the substrate11, wherein the patterned structure is composed of the graphene oxidecatalytic layer 13 and the metal layer 14. In one embodiment, thesubstrate 11 is an insulation material or a semiconductor material. Inthis embodiment, the graphene oxide layer 12 is used as an insulationbarrier layer, and the graphene oxide catalytic layer 13 is used as anelectroplating seed layer for thickening the metal layer 14.Alternatively, in another embodiment, the metallization may be completedby performing, for example, an electroless plating directly on thegraphene oxide catalytic layer 13.

FIG. 2 illustrates another patterned metallization structure 20 inaccordance with another embodiment of the present disclosure. Thepatterned metallization structure 20 includes a substrate 21, a grapheneoxide catalytic layer 23, a metal layer 24, and a dielectric layer 25.The dielectric layer 25 is disposed on the substrate 21 and haspatterned first openings 26. The graphene oxide catalytic layer 23 isdisposed on the inner edge of the first openings 26 and is in contactwith the dielectric layer 25 and the substrate 21. In this embodiment, apatterned structure is disposed above the substrate 21, wherein thepatterned structure is composed of the graphene oxide catalytic layer23, the metal layer 24, and the dielectric layer 25. In one embodiment,the substrate 21 is an insulation material or a semiconductor material.It should be noted that there may be a graphene oxide layer 22 disposedbetween the graphene oxide catalytic layer 23 and the dielectric layer25. When there is a graphene oxide layer 22, the graphene oxide layer 22is in contact with the dielectric layer 25 and the substrate 21. Also,in such cases, the graphene oxide catalytic layer 23 is disposed betweenthe graphene oxide layer 22 and the metal layer 24. In this embodiment,a patterned structure is disposed above the substrate 21, wherein thepatterned structure is composed of the graphene oxide layer 22, thegraphene oxide catalytic layer 23, the metal layer 24, and thedielectric layer 25. It should be noted that the graphene oxidecatalytic layer 23 and graphene oxide layer 22 do not have to exist atthe same time.

The graphene oxide catalytic layer is formed by performing a surfacemodification of the graphene oxide layer by using a metal complex. Inother words, during the surface modification of the graphene oxidelayer, a redox reduction is induced and a metal deposition is occurred,thereby forming the graphene oxide catalytic layer. During the surfacemodification, the deposited metal may permeate into the graphene oxidelayer. The graphene oxide layer permeated with metal is also consideredas the graphene oxide catalytic layer in the present disclosure.Therefore, after the surface modification, the original graphene oxidelayer may be replaced by the graphene oxide catalytic layer.Alternatively, after the surface modification, the graphene oxidecatalytic layer and the graphene oxide layer may exist at the same time.The drawings of the present disclosure only illustrate cases in whichthe graphene oxide catalytic layer and the graphene oxide layer exist atthe same time. However, it is not intended to be limiting.

In some embodiments, the substrate used in the present disclosure may bemade of ceramic materials such as oxides, nitrides, glass, polymers,silicon wafers and so on. In some embodiments, the material of the metallayer may be nickel and its alloys, copper, cobalt, gold, silver, tin,and so on. The metallization structure of the present disclosure may bewidely applied to the metallization of fine pitch of semiconductor andits package, fine pitch wires of printed circuit board (PCB), touchpanels, displays, fine electrodes of solar cells, and so on.

In the present disclosure, graphene oxide was prepared in the mannerdescribed by Hummer's method (J. Am. Chem. Soc., 1958, 80 (6), 1339).

0.5 g of graphite powder and 0.5 g of sodium nitrate were added to 23 mlof 98% concentrated sulfuric acid and stirred in an ice-water bath.After thorough mixing, 3 g of potassium permanganate was slowly addedand stirred in an ice-water bath for 15 minutes. The solution was heatedto 35° C. and the temperature was kept for 30 minutes. Then, 46 ml ofpure water was slowly added. The solution was heated to 98° C. and thetemperature was maintained for 15 minutes. Finally, 140 ml of pure waterwas added for dilution and 25 ml of 30% hydrogen peroxide was added tostop the reaction.

The following describes the method for manufacturing the metallizedstructure according to an embodiment of the present disclosure incooperation with FIG. 3A to FIG. 3E. First, referring to FIG. 3A, asubstrate 301 was provided. The substrate 301 may be ceramic materialssuch as oxides or nitrides, glass, polymers, silicon wafers and so on.In one embodiment of the present disclosure, the substrate 301 is glass.Then, a graphene oxide layer 302 is formed on the substrate 301. Themethod for forming the graphene oxide layer 302 may be sputteringmethod, coating method, spin coating method, knife coating method, slitdie coating method, roll coating method, dip coating method, immersionmethod, chemical vapor deposition (CVD) method, and so on. Referring toFIG. 3B, a mask 304 with a second opening 303 is provided on thesubstrate 301 which includes the graphene oxide layer 302 to form apattern. Thereafter, referring to FIG. 3C, a metal complex is used tomodify the graphene oxide layer 302 in the second opening 303 to form agraphene oxide catalytic layer 305. Examples of the modification methodfor the graphene oxide layer 302 include an ultrasonic method, animpregnation method, a thermal treatment method, a microwave method, aUV light irradiation method, an electrochemical method, and a highpressure method. The metal complex may be precious metal complexes suchas copper complex, gold complex, nickel complex, silver complex,palladium complex, platinum complex, or rhodium complex. In oneembodiment of the present disclosure, the graphene oxide layer 302 ismodified by using palladium ion complexes (PdCl₄ ²⁻, Pd(NH₃)₄Cl₂, PdCl₆²⁻, Pd(acac)₂, Pd(OAc)₂) or silver ion complexes (Ag⁺, [Ag(NH₃)]⁺,Ac—Ag). Then, referring to FIG. 3D, a metallization process is performedon the second opening 303 to form a metal layer 306. Thereafter,referring to FIG. 3E, the mask 304 is removed.

In another embodiment, referring to FIG. 4A to FIG. 4F, a passivationlayer 402 (or a protective layer, or a dielectric layer) is formed onthe substrate 401. Then, a graphene oxide layer 403 is formed on thepassivation layer 402. Referring to FIG. 4C, a mask 405 with a thirdopening 404 is provided on the substrate 401 which includes thepassivation layer 402 and the graphene oxide layer 403 to form apattern. Thereafter, referring to FIG. 4D, a metal complex is used tomodify the graphene oxide layer 403 in the third opening 404 to form agraphene oxide catalytic layer 406. Then, referring to FIG. 4E, ametallization process is performed on the third opening 404 to form ametal layer 407. Thereafter, referring to FIG. 4F, the mask 405 isremoved.

In some embodiments, the thickness of the graphene oxide catalytic layermay be ranging from 0.5 nm to 100 nm. For example, in some embodiments,the thickness of the graphene oxide catalytic layer may be ranging from0.7 nm to 50 nm. It should be noted that, if the graphene oxide layerand graphene oxide catalytic layer exist at the same time, the totalthickness of the graphene oxide layer and graphene oxide catalytic layermay range from 0.5 nm to 100 nm. For example, in some embodiments, thetotal thickness of the graphene oxide layer and graphene oxide catalyticlayer may range from 0.7 nm to 50 nm.

According to the above description, the present disclosure uses grapheneoxide as an insulation barrier layer, and a specific area of thegraphene oxide is modified to induce a redox reaction, resulting metaldeposition and forming a graphene oxide catalyst layer. The grapheneoxide catalyst layer can be used as a seed layer. The metallizationstructure provided by the present disclosure has the followingadvantages: elimination of an etching process, avoidance of warpage,reduction of undercut, reduction the formation of poor metal profile orwire collapse, and so on. Also, the method provided by the presentdisclosure can be used to prepare fine pitch wire metallization, improvethe reliability and yield.

In one embodiment of the present disclosure, a metallization structureis provided. The metallization structure includes a substrate, agraphene oxide and graphene oxide catalytic layer, and a metal layer,wherein the graphene oxide catalytic layer is disposed between thesubstrate and the metal layer. In some embodiments, the substrate may bean insulation material or a semiconductor material. In some embodiments,the metallization structure of the present disclosure may furtherinclude a graphene oxide layer, disposed between the substrate and thegraphene oxide catalytic layer.

In another embodiment of the present disclosure, a patternedmetallization structure is provided. The patterned metallizationstructure includes a substrate, a graphene oxide catalytic layer, ametal layer, and a dielectric layer. The dielectric layer is disposed inthe substrate and has patterned openings. The graphene oxide catalyticlayer is disposed on the inner edge of the openings. The substrate maybe an insulation material or a semiconductor material. In someembodiments, the patterned metallization structure of the presentdisclosure may further include a graphene oxide layer, disposed betweenthe graphene oxide catalytic layer and the dielectric layer and/orbetween the graphene oxide catalytic layer and the substrate.

In some embodiments of the present disclosure, a metal diffusion barrierlayer, a passivation layer, or a protective layer may be further formedon the substrate which includes a patterned structure or not.

In another embodiment of the present disclosure, a method for formingthe metallization structure is also provided. The method includesproviding a substrate, forming a graphene oxide layer on the substrate;modifying the graphene oxide layer to form a graphene oxide catalyticlayer; and performing a metallization process on the graphene oxidecatalytic layer.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed embodiments.It is intended that the specification and examples be considered asexemplary only, with the true scope of the disclosure being indicated bythe following claims and their equivalents.

What is claimed is:
 1. A method for forming the metallization structure,comprising: providing a substrate; forming a graphene oxide layer on thesubstrate; modifying the graphene oxide layer to form a graphene oxidecatalytic layer; and performing a metallization process on the grapheneoxide catalytic layer.
 2. The method for forming the metallizationstructure as claimed in claim 1, further comprising performing apatterning process after providing the substrate.
 3. The method forforming the metallization structure as claimed in claim 1, whereinmodifying the graphene oxide layer is performed by providing a metalcomplex.
 4. The method for forming the metallization structure asclaimed in claim 3, wherein the metal complex comprises copper complex,gold complex, nickel complex, silver complex, palladium complex,platinum complex, or rhodium complex.
 5. The method for forming themetallization structure as claimed in claim 1, wherein the metallizationprocess is performed by electroless plating.